Method for preparing hydrazo-bis-acetonitriles

Abstract

This invention relates to a method for preparing hydrazo-bis-acetonitriles of the general formula: ##EQU1## wherein R 1 and R 2 have the same meaning hereinafter given, which comprises: A. i. reacting a carbonyl compound of the general formula: ##EQU2## wherein R 1 and R 2 have the same meaning hereinafter given, with ammonia and hydrogen peroxide in the presence of cyanogen or a nitrile of the formula R.sub.3 (CN).sub.n (III) wherein n is an integer from 1 to 6 and R 3 is an unsubstituted or substituted saturated aliphatic, acyclic or cyclic radical of from 1 to 12 carbon atoms or a benzenyl or pyridinyl radical, to form a symmetrical azine of the formula ##EQU3## ii. oxidizing a secondary alcohol of ##EQU4## wherein R 1 and R 2 have the same meaning hereinafter given, at a temperature and pressure which is sufficient to maintain the alcohol in the liquid phase and result in a liquid phase mixture containing the peroxidic products of the auto-oxidation of the alcohol [v] and reacting auto-oxidation products with ammonia and cyanogen or the nitrile R 3 (CN) n of formula (III) to form the symmetrical azine of formula (IV) b. eliminating unreacted ammonia from the medium resulting from (a); C. reacting the azine of formula (IV) contained in the ammonia-free medium resulting from (b) with at least two moles of hydrocyanic acid per mole of azine; and D. recovering the hydrazo-bis-acetonitrile of formula (I).

We claim: 
     
       1. A method for preparing hydrazo-bis-acetonitriles of the general formula ##EQU5## wherein R 1  is hydrogen and R 2  or R 1  and R 2  each is a straight chain alkyl radical of from 1 to 12 carbon atoms, a branched chain alkyl radical of from 3 to 12 carbon atoms, a cycloalkyl radical of from 3 to 12 carbon atoms or a phenyl radical or R 1  and R 2  together form a straight or branched chain alkylene radical of from 4 to 12 carbon atoms being unsubstituted or substituted with one or more chloro, bromo or fluoro atoms or nitro or methoxy groups, which consists essentially of: a. reacting in a single reaction medium (i) a carbonyl compound of the general formula ##EQU6## wherein R 1  is hydrogen and R 2  or R 1  and R 2  each is a straight chain alkyl radical of from 1 to 12 carbon atoms, a branched chain alkyl radical of from 3 to 12 carbon atoms, a cycloalkyl radical of from 3 to 12 carbon atoms or a phenyl radical or R 1  and R 2  together form a straight or branched chain alkylene radical of from 4 to 12 carbon atoms being unsubstituted or substituted with one or more chloro, bromo or fluoro atoms or nitro or methoxy groups, (ii) ammonia, (iii) hydrogen peroxide, and (iv) cyanogen or a nitrile of the formula   R.sub.3 (CN).sub.n                                         (III)       wherein n is an integer from 1 to 6 and R 3  is a straight chain alkyl radical of from 1 to 12 carbon atoms, a branched chain alkyl radical of from 3 to 12 carbon atoms, a cycloalkyl radical of from 3 to 12 carbon atoms or a benzene or pyridine radical, said radical being unsubstituted or substituted with one or more halogen atoms or carbamyl, carboxylic, nitro, hydroxy, epoxy, or sulfonic acid groups, to form a symmetrical azine of the formula ##EQU7## b. eliminating unreacted ammonia from the medium resulting from (a) by evaporating unreacted ammonia at atmospheric or reduced pressure, or by neutralizing the unreacted ammonia with at least a stoichiometric amount of hydrochloric acid, phosphoric acid, sulfuric acid, formic acid or acetic acid;   c. reacting the ammonia-free medium resulting from (b) with at least two moles of hydrocyanic acid per mole of azine; and   d. recovering the hydrazo-bis-acetonitrile of Formula (I).   
     
     
       2. The method of claim 1 wherein the carbonyl compound (II) is acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valerylaldehyde, pivalaldehyde, oenanthal, hexahydrobenzaldehyde, p-nitrobenzaldehyde or β-methoxy-propionaldehyde. 
     
     
       3. The method of claim 1 wherein the carbonyl compound (II) is acetone, 2-butanone, 2-pentanone, 3-pentanone, methylisopropylketone, methylisobutylketone, methylcyclohexylketone, acetophenone, benzophenone, cyclobutanone, cyclopentanone, cyclohexanone, 2-methylcyclohexanone, 4-methylcyclohexanone, 2,4-dimethylcyclohexanone, 3,3,5-trimethylcyclohexanone, cycloheptanone, cyclooctanone, cyclodecanone or cyclododecanone. 
     
     
       4. The method of claim 1 wherein the nitrile is added to the reaction medium of step (a). 
     
     
       5. The method of claim 1 wherein from about 0.2 to about 5 moles of carbonyl compound and ammonia per mole of hydrogen peroxide are reacted. 
     
     
       6. The method of claim 1 wherein from about 1 to about 10 molar equivalents of nitrile per mole of hydrogen peroxide are present in the reaction medium. 
     
     
       7. The method of claim 1 wherein from about 0.01 to 2% by weight of an ammonium or alkaline metal salt of a hydracid, mineral oxyacid, aromatic or aliphatic carboxylic acid or alkyl or arylsulfonic acid, all of the above having less than about 20 carbon atoms, and wherein the anions are stable under the oxidizing conditions of the reaction medium is added as a catalyst to the reaction medium of step (a). 
     
     
       8. The method of claim 1 wherein at least part of the unreacted carbonyl compound (II) present in the reaction medium is removed therefrom before carrying out step (c). 
     
     
       9. The method of claim 1 wherein hydrocyanic acid is used in excess up to about 100% of the theoretically required amount. 
     
     
       10. The method of claim 1 wherein the temperature of the reaction of step (c) is maintained between about 0° and 100° C. 
     
     
       11. The method of claim 1 wherein step (b) is carried out by neutralizing the unreacted ammonia with at least a stoichiometric amount of hydrochloric acid, phosphoric acid, sulfuric acid, formic acid or acetic acid. 
     
     
       12. The method of claim 1 wherein the nitrile (III) is acetonitrile, propionitrile, butyronitrile, isobutyronitrile, cyclohexylcarboxylic nitrile, benzonitrile, a tolunitrile, a cyanopyridine, mono-, di- or trichloroacetonitrile, m-chlorobenzonitrile, p-methoxybenzonitrile, p-nitrobenzonitrile, m-trifluoromethylbenzonitrile, glycolonitrile, epsilon-hydroxycapronitrile, cyanoacetic acid, an amide or alkyl ester of cyanoacetic acid, an amide or alkyl ester of beta-cyanopropionic acid, malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, a phthalonitrile, beta-hydroxypropionitrile, β,β'-oxydipropionitrile, a β-alkoxypropionitrile or a nitrile prepared from the cyanoethylation with acrylonitrile or methacrylonitrile of ethyleneglycol, propyleneglycol, glycerol, sorbitol or water. 
     
     
       13. The method of claim 12 wherein the nitrile prepared by cyanoethylation is formed in situ within the reaction medium of step (a). 
     
     
       14. A method for preparing hydrazo-bis-acetonitriles of the general formula ##STR11## wherein R 1  is hydrogen and R 2  or R 1  and R 2  each is a straight chain alkyl radical of from 1 to 12 carbon atoms, a branched chain alkyl radical of from 3 to 12 carbon atoms, a cycloalkyl radical of from 3 to 12 carbon atoms or a phenyl radical or R 1  and R 2  together form a straight or branched chain alkylene radical of from 4 to 12 carbon atoms being unsubstituted or substituted with one or more chloro, bromo or fluoro atoms or nitro or methoxy groups, which consists essentially of: a. oxidizing a secondary alcohol of the general formula ##STR12## wherein R 1  and R 2  each is a straight chain alkyl radical of from 1 to 12 carbon atoms, a branched chain alkyl radical of from 3 to 12 carbon atoms, a cycloalkyl radical of from 3 to 12 carbon atoms or a phenyl radical or R 1  and R 2  together form a straight or branched chain alkylene radical of from 4 to 12 carbon atoms being unsubstituted or substituted with one or more chloro, bromo or fluoro atoms or nitro or methoxy groups, with molecular oxygen or a gaseous mixture consisting essentially of molecular oxygen, at a temperature and pressure which is sufficient to maintain the alcohol in the liquid phase to produce a mixture containing the peroxidic products of the auto-oxidation of the alcohol (V), said mixture being free of heavy metal ions, and reacting the auto-oxidation products with ammonia and cyanogen or a nitrile of the formula   R.sub.3 (CN).sub.n                                         (III)     wherein n is an integer from 1 to 6 and R 3  is a straight chain alkyl radical of from 1 to 12 carbon atoms, a branched chain alkyl radical of from 3 to 12 carbon atoms, a cycloalkyl radical of from 3 to 12 carbon atoms or a benzene or pyridine radical, said radical being unsubstituted or substituted with one or more halogen atoms or carbamyl, carboxylic, nitro, hydroxy, epoxy, or sulfonic acid groups, to form a symmetrical azine of the formula ##STR13## b. eliminating unreacted ammonia from the medium resulting from (a) by evaporating unreacted ammonia at atmospheric or reduced pressure, or by neutralizing the unreacted ammonia with at least a stoichiometric amount of hydrochloric acid, phosphoric acid, sulfuric acid, formic acid or acetic acid;     c. reacting the ammonia-free medium resulting from (b) with at least two moles of hydrocyanic acid per mole of azine; and   d. recovering the hydrazo-bis-acetonitrile of formula (I).   
     
     
       15. The method of claim 14 wherein the alcohol (V) is selected to be isopropanol, 2-butanol, 2-pentanol, 3-methyl-2-butanol, 4-methyl-2-pentanol, 2-octanol, 1-cyclohexylethanol, 1-phenylethanol, diphenylcarbinol, cyclobutanol, cyclopentanol, cyclohexanol, 2-methylcylohexanol, 3-methylcyclohexanol, 3,3,5-trimethylcyclohexanol, cycloheptanol, cyclooctanol or cyclododecanol. 
     
     
       16. The method of claim 14 wherein from about 0.01 to 2% by weight of a ketone peroxide, hydrogen peroxide, tertiobutyl peroxide of azobisisobutyronitrile is added to the reaction medium of step (a) to facilitate the oxidation of the alcohol (V). 
     
     
       17. The method of claim 14 wherein unreacted alcohol (V) is removed from the mixture of peroxidic products before reacting the latter with ammonia, cyanogen or nitrile (III). 
     
     
       18. The method of claim 14 wherein ammonia is utilized in step (a) at a level of from about 0.2 to 5 moles per equivalent of peroxidic oxygen. 
     
     
       19. The method of claim 14 wherein nitrile (III) is utilized in step (a) at a level of from about 1 to 10 moles per equivalent of peroxidic oxygen. 
     
     
       20. The method of claim 14 wherein the reaction of the auto-oxidation products of step (a) with ammonia, and cyanogen or nitrile (III) is maintained at a temperature between about 0° and 100° C. 
     
     
       21. The method of claim 14 wherein the nitrile (III) is acetonitrile, propionitrile, butyronitrile, isobutyronitrile, cyclohexylcarboxylic nitrile, benzonitrile, a tolunitrile, a cyanopyridine, mono-, di- or trichloroacetonitrile, m-chlorobenzonitrile, p-methoxybenzonitrile, p-nitrobenzonitrile, m-trifluoromethylbenzonitrile, glycolonitrile, epsilon-hydroxycapronitrile, cyanoacetic acid, an amide or alkyl ester of cyanoacetic acid, an amide or alkyl ester of beta-cyanopropionic acid, malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, a phthalonitrile, beta-hydroxypropionitrile, β,β'-oxydipropionitrile, a β-alkoxypropionitrile or a nitrile prepared from the cyanoethylation with acrylonitrile or methacrylonitrile of ethyleneglycol, propyleneglycol, glycerol, sorbitol or water. 
     
     
       22. The method of claim 14 wherein from about 0.01 to 2% by weight of an ammonium or alkaline metal salt of a hydracid, mineral oxyacid, aromatic or aliphatic carboxylic acid or alkyl or arylsulfonic acid containing less than about 20 carbon atoms and wherein the anions are stable under the oxidizing conditions of the reaction medium is added as a catalyst to the reaction medium of step (a). 
     
     
       23. The method of claim 14 wherein step (b) is carried out by neutralizing the unreacted ammonia with at least a stoichiometric amount of hydrochloric acid, phosphoric acid, sulfuric acid, formic acid or acetic acid. 
     
     
       24. The method of claim 14 wherein hydrocyanic acid is used in excess up to about 100% of the theoretically required amount. 
     
     
       25. The method of claim 14 wherein the temperature of the reaction of step (c) is maintained between about 0° and 100° C.